Pet Rescue Level 29 Strategy
First of all try to rescue the two pets under the locked blocks before use the key. When you’ve done this, clear as more blocks as possible and only then use the key to unlock the blocks. After that rescue and the other three pets. You can be helped in this task by the rocket booster, that gets activated in the level.
Pet Rescue Level 29 Walkthrough Video
Helpful walkthrough video in order to beat Pet Rescue Level 29: